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Old   October 5, 2007, 09:18
Default Grid check failed
  #1
Norasikin Mat Isa
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Hello everyone! I created a 2D mesh in GAMBIT but when I import it in fluent 6 I have a warning during check Grid: "WARNING: non-positive face area exist!" What's the problem? Please, can someone help me. Thank you.

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Old   October 5, 2007, 09:24
Default Re: Grid check failed
  #2
PratiK Mehta
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first check if u have saved the *msh file by ticking export 2d .Also so whether u have opened 2d fluent n not 3d
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Old   October 5, 2007, 09:27
Default Re: Grid check failed
  #3
Norasikin Mat Isa
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I've checked that. But I still get the same warning. Thanks.
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Old   October 5, 2007, 09:29
Default Re: Grid check failed
  #4
PratiK Mehta
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I guess then u should check it out in gambit to remesh the system. What mesh are u using
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Old   October 5, 2007, 09:34
Default Re: Grid check failed
  #5
Norasikin Mat Isa
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I used tri. I made a triangle shape at inlet as I want fine meshing there and I mesh the rest.
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Old   October 5, 2007, 09:46
Default Re: Grid check failed
  #6
PratiK Mehta
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Cells with a negative volume can often be identified using the Iso-Value Adaption capability to mark them for adaption and view them in the graphics window.

Have u mentioned the dimensions of the domain correctly.

Negative volumes means that u have disconnectivity within your domain, so make sure u have done a connectivity check in gambit.
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Old   October 5, 2007, 10:06
Default Re: Grid check failed
  #7
Norasikin Mat Isa
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Thanks. I will try that. One more question. Which one should I do first?... grid - check.. or define - solver ( axisymmetric)?.. because.. if i do grid - check first.. i won't get that message... if i do define- solver.. then grid check... i will get that message. Can you explain why?. I do just half of tank and have an axis. Thank.

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Old   October 6, 2007, 23:32
Default Re: Grid check failed
  #8
Sun
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make sure that the min volume isn't negative during Grid checking
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Old   October 7, 2007, 22:55
Default Re: Grid check failed
  #9
WTTO
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Before import mesh to FLUENT, check your grid in GAMBIT and make sure that the negative volume not exist by examine mesh tool. If still there, you can redistribute mesh untill you get free of negative volume (area).
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Old   October 11, 2007, 03:44
Default Re: Grid check failed
  #10
Rameche Candane
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What you are supposed to do is the following:

When you create the geometry try creating it in mm (millimeters) rather than in m. Its obvious that you cant specify the unit in GAMBIT but create the geometry in mm (ex if the length is 1meter make it 1000 mm if not create it in cms) Then try reading the mesh in FLUENT after specifying the scale there as mm you wont have any problem.

Regards, Rameche Candane. S

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